Machines for feeding and closing partially formed and filled cartons are well-known in the art. For many years, the most successful approach for feeding cartons along an entire carton forming line, including for closing and sealing the lid and flaps, was performed by conveyors in-line with fixed lugs or flights mounted on chains, as shown in U.S. Pat. No. 3,267,637 to Baker, which is incorporated herein by reference. These chains moved the cartons forward by pushing along the rear or trailing end. At various transition locations along the carton forming line, it was necessary to turn the carton about its vertical axis while continuing to feed the carton forward. Usually, this turning motion was through 90 degrees and was performed in one fashion or another, such as by using a plurality of spaced belts running at different speeds, a kick-out mechanism, or the like.
A modern and commercially successful approach to continuous carton forming is found in commonly assigned U.S. Pat. No. 5,660,262 to Landrum et al., the disclosure of which is also incorporated herein by reference. In this arrangement, infeed belts frictionally engage the top and bottom surfaces of the carton for conveying while the front flap is sealed. This eliminates the need for pre-folding the trailing end flap to avoid damaging it, as is required when using upstanding lugs. After the front flap is sealed, the carton enters a zone with a kick-out lug to engage a leading side of the carton, retard its motion and cause it to start to turn. A plurality of spaced parallel belts running at different speeds then continue to reorient the carton, such as with turning through 90° in the same plane. The turned carton is then received and conveyed by spaced belts while the opposite side flaps are folded and sealed. The carton is thus formed in a continuous fashion without stopping or changing the conveying direction.
While this type of approach has enjoyed considerable commercial success, the use of belts running at differential speeds to turn the carton during feeding increases the complexity of the machine, as well as the resulting footprint. Maintenance costs are also increased in view of the need for ensuring that the speed of the belts is proper for turning the carton in the desired fashion. Modern times also demand faster throughput than can be afforded using frictional engagement alone to accomplish turning.
Accordingly, a need exists for an improved carton feeding and forming machine that overcomes the foregoing limitations and others.